For surfactants and surface treatment agents with fluorochemical chains, longer perfluoroalkyl chains contain a higher percentage of fluorine at a given concentration and typically provide better performance. However, the fluorinated materials derived from longer perfluoroalkyl chains are more expensive. Reduction of the fluorine content with delivery of the same or higher performance is therefore desirable. Reducing the fluorine content would reduce the cost, but it is necessary to maintain product performance.
U.S. Ser. No. 11/890,414 filed Aug. 8, 2007, discloses fluoroalkyl-alkyl twin tailed phosphate surfactants which have two dissimilar terminal hydrophobic groups attached to a single connecting group. U.S. Pat. No. 5,643,864 discloses anionic surfactants having at least two hydrophobic chains and at least two hydrophilic groups per molecule useful as emulsifiers, detergents, dispersant and solubilizing agents.
It is desirable to improve surfactant performance, in particular lowering of surface tension in aqueous systems, and to increase the fluorine efficiency, i.e., boost the efficiency or performance of the surfactants so a lower proportion of the expensive fluorine component is required to achieve the same level of performance, or to have better performance using the same level of fluorine. Especially desirable would be surfactants having both a hydrophobic and a hydrophilic group in the same compound which are fluorine efficient. It is also desirable to have surfactants that are stable in brine and aggressive media (acid and base) while still maintaining improved performance. The present invention provides such surfactants.